The present invention relates to a directional antenna and in particular, the spacing between the radiating and directing elements of the antenna.
In some radio communication applications, a radio operator finds it mandatory to communicate with a distant station located in a particular direction. This is particularly important for a radio operator when: a distant station is difficult to hear, the distant station cannot hear the radio operator, or the radio operator wishes to reduce adjacent station interference from another station located in a different direction than the distant station. To accomplish this task, directional antennas are used. Directional antennas are used to boost the effective transmitted radiated power and increase the receiving sensitivity of a station to other stations in a desired direction. Current solutions are found in multi-element antennas (such as a Yagi or a Quad). These antennas generally contain elements which are separated by a half wavelength. Such antennas are usually large in size and may be impracticable to erect in certain locations. A large antenna is also susceptible to wind loading (which could lead to eventual material failure). Additionally, there is always a desire for an antenna with higher performance.
U.S. Pat. No. 2,183,784 for “Directional Antenna,” discloses an array of vertically spaced apart antennas. Each antenna comprises a driven element and a directing element, with the antennas vertically spaced apart by approximately one half wavelength. The '784 patent discloses a maximum gain with a horizontal spacing between the driven and directing elements of 0.2 wavelengths and a minimum back radiation with a horizontal spacing between 0.25 and 0.3 wavelengths. While the antenna of the '784 patent achieves some improvement over previous antennas, it also creates wind load issues and even greater improvements are desired. The '784 patent is herein incorporated by reference.
Therefore, a need remains for a directional antenna design which possesses higher gain and a more compact design than present technology antennas with larger footprints and a lesser gain.